In nominal flight missions, an aircraft flies from its origination point to its intended destination, and is able to evaluate the landing site in order to determine an appropriate touchdown location within the landing site. In nominal flight missions, the aircraft, whether piloted or autonomous, is able to detect and avoid obstacles, and is able to navigate with or without a functioning GPS system. Nominal flight missions do not include contingency landings, which might be required immediately after failure of an important aircraft system, such as an engine or key sensors systems, including state estimation sensors for autonomous aircraft. When such a contingency occurs, the aircraft may have to make an immediate landing at a site that did not receive the typical evaluation associated with a nominal flight mission.